I. Field
The present disclosure relates generally to wireless communications and more specifically to radio bearer establishment.
II. Background
Wireless communication systems are widely deployed to provide various types of communication content such as, for example, voice, data, and so on. Typical wireless communication systems may be multiple-access systems capable of supporting communication with multiple users by sharing available system resources (e.g., bandwidth, transmit power, . . . ). Examples of such multiple-access systems may include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, and the like. Additionally, the systems can conform to specifications such as third generation partnership project (3GPP), 3GPP long term evolution (LTE), ultra mobile broadband (UMB), and/or multi-carrier wireless specifications such as evolution data optimized (EV-DO), one or more revisions thereof, etc., which can utilize evolved universal terrestrial radio access (E-UTRA) to facilitate radio communication between wireless devices. E-UTRA can also be utilized in evolved packet systems (EPS), such as 3GPP LTE.
Generally, wireless multiple-access communication systems may simultaneously support communication for multiple mobile devices. Each mobile device may communicate with one or more base stations via transmissions on forward and reverse links. The forward link (or downlink) refers to the communication link from base stations to mobile devices, and the reverse link (or uplink) refers to the communication link from mobile devices to base stations. Further, communications between mobile devices and base stations may be established via single-input single-output (SISO) systems, multiple-input single-output (MISO) systems, multiple-input multiple-output (MIMO) systems, and so forth. In addition, mobile devices can communicate with other mobile devices (and/or base stations with other base stations) in peer-to-peer wireless network configurations.
In E-UTRA networks, base stations or other access points can establish bearers with mobile devices at a radio communication layer, such as radio resource control (RRC) layer, to support multiple levels of service relating to varying types of communications. The base stations can establish the bearers with the mobile devices based on requests from the core network (e.g., where the core network authorizes the mobile devices for communication based on a network access request). To this end, the network generates and appends a non-access stratum (NAS) message to the bearer setup requests, such that the base stations can receive the requests, initialize the bearers, and forward the NAS message to the mobile devices. The NAS message facilitates setup and subsequent utilization of the bearers by the mobile devices.
In Universal Mobile Telecommunication System (UMTS) networks, a network can establish only one new bearer at one time. In E-UTRA and EPS, multiple new bearers can be established simultaneously. To this end, one possible implementation is that the NAS message relates to multiple bearers and is appended to the bearer setup request, which is generated by the network and transmitted to a base station, using a single NAS packet data unit (PDU) for all bearers. In some cases, the base station is not able to initialize one or more bearers indicated in the bearer setup request (e.g., due to admission control and/or the like), and the base station indicates failure of the entire bearer setup request to the network. Typically, based on receiving the failure, the core network can attempt different combinations of bearers and related NAS messages transmitted in new bearer setup requests until the base station can successfully setup the requested bearers for the mobile device.